Please advise...

[Kali]

6. I'm with mo, get a couple goats for brush, sheep for grass

not sure about fertilizer for corn flowing downhill, but if you have been cutting and removing a lot of plant material for a long period of time the soil may be depleted. that may affect blooming and even fruit trees. I would replant fruit trees for sure if I lost them. they will need some kind of organic matter/fertilizer on a regular basis.

what is the size area you want cleared, is this once per year or some kind of ongoing maintenance? a regular landscape company may actually be what you need, be upfront about sprays and other chemicals. if they can't/won't work with you keep looking.